Thank you all for swift and easy to understand answers! It works! I knew there had to be an easier way to do it than I was. I was opening both files twice each. I think I was up to 40 lines.

I based my solution on what Eimi Metamorphoumai proposed. Thank you Eimi!

Here is what I ended up with

    foreach (@bz_comments){
        ($who, $bug_id, undef, $date, undef, $body) = split(/,/, $_); 
        $BZ_comment{$bug_id} .= "<p><strong>$who $date</strong></p> <p
+>$body</p>";
    }
    
    while (my ($id, $comment) = each %BZ_comment){
        push(@bz_comments_OUTPUT, "$id , $comment");
    }
[download]

Thank you all again!

Jamin